A two-cycle engine (also referred to as a “two-stroke engine”) is a reciprocating engine in which one cycle of intake, compression, combustion, and exhaust is performed in each reciprocating motion of a piston inside a cylinder. In the two-cycle engine, in general, in order to keep the sliding performance of the piston (piston rings) inside the cylinder, a lubricant is supplied to a sliding surface of the cylinder from a lubrication port provided in the cylinder.
Patent Document 1 discloses a cylinder lubrication device provided in a diesel engine for a large ship. The cylinder lubrication device controls an opening timing and an opening period of a solenoid valve based on a crank angle and a rotational speed of the engine. Specifically, the opening timing and the opening period of the solenoid valve are controlled so that a lubricator supplies the lubricant at least one time in each reciprocating motion of the piston into an inter-ring space formed between piston rings. In addition, the cylinder lubrication device supplies the lubricant into at least the uppermost inter-ring space during the upward movement of the piston (refer to paragraph [0019] in the specification of Patent Document 1).